1) PulseAudio's alsa plugin should honor the requested latency from the call to snd_pcm_set_params() by setting pa_buffer_attr.fragsize accordingly.
2) PulseAudio's alsa plugin should honor ALSA calls to snd_pcm_drain() -- which I think are most likely the cause of the audio cutoff when combined with the high latency.
Two other things:
1) PulseAudio's alsa plugin should honor the requested latency from the call to snd_pcm_ set_params( ) by setting pa_buffer_ attr.fragsize accordingly.
2) PulseAudio's alsa plugin should honor ALSA calls to snd_pcm_drain() -- which I think are most likely the cause of the audio cutoff when combined with the high latency.